1. Field of the Invention:
The present invention relates to a method of manufacturing a thin film magnetic head, and more particlarly, to a method of forming the thin film magnetic head by employing a substrate which is completely subjected to a thin film forming process.
2. Description of the Prior Art:
A method of manufacturing a thin film magnetic head which completely undergoes a thin film forming process will hereinafter be described with reference to FIGS. 5 to 7. A protection film 12 is, as illustrated in FIG. 5(a), laminated on a non-magnetic substrate 11 wherein a prerequisite thin film forming process is completed. This non-magnetic substrate 11 is cut along the cutting-plane lines A-A' and B-B' and is then subjected to a slider processing, thus forming a thin film magnetic head 10 (FIG. 5(b)). Subsequently, the surface of the protection film 12 thereof is uniformly ground; and bonding pads 13 formed on the non-magnetic substrate 11 are exposed, thereby completing the formation of the thin film magnetic head 10 (FIG. 5(c)). Lead wires are afterward connected to the bonding pads 13. The grinding operation of the surface of the protection film 12 may often be performed prior to the slider processing.
The bonding pads 13 are, as illustrated in FIGS. 7(a), 7(b), formed by plating or other similar methods on a lead terminal 14 of coils 14 produced by a thin film forming technique on the non-magnetic substrate 11. The reference numeral 22 stands for an insulating layer which covers the lower circumference of the bonding pads 13. The coils 14 are, as shown in FIGS. 6(a), 6(b), concentrically disposed round the center, viz., a back gap 17 formed between a lower magnetic layer 15 and an upper magnetic layer 16; and the circumference thereof is covered with an insulator layer 18. An insulator layer 20 is inserted in a front gap 19, videlicet, this layer 20 is interposed between the lower magnetic layer 15 and the upper magnetic layer 16, thus constituting the magnetic gap 19. The numeral 21 represents a base film formed on the non-magnetic substrate 11. The above-described components are provided on the non-magnetic substrate 11 so that each component is disposed in two sets on the respective thin film magnetic heads 10. A technology to form a film relative to the above-mentioned components which requires an etching process is well known, and this is not associated with the present invention. Further description is therefore omitted for convenience.
According to the conventional method of manufacturing the thin film magnetic head, when the surface of the protection film 12 is uniformly ground and the bonding pads 13 are exposed, the upper magnetic layer 16 (magnetic core) must not be ground. For this reason, a height of the bonding pad has to be sufficiently greater than that of the upper magnetic layer 16, and at the same time the protection film has to be considerably thick, taking a grinding allowance into consideration. The surface grinding operation of the protection film 12 is carried out after cutting out the thin film magnetic heads 10 from the non-magnetic substrate 11. Consequently, even if such consideration be a given, there will be probability for the upper magnetic layer 16 to be ground, depending on dispersiveness of the respective thin film magnetic heads and on the bonding accuracy of a jig. Hence, there arise problems wherein it is difficult to improve the yield and to reduce the number of required processes.